gh-95841: IDLE - Revise Windows local doc url (GH-95845) (#95905)

GH-91242 replaced the Windows chm help file with a copy
of the html docs.  This PR replaces the IDLE code that
fetches the Windows local help url passed to os.startfile.

Co-authored-by: Terry Jan Reedy <tjreedy@udel.edu>
Co-authored-by: Steve Dower
Approved by Steve Dower, #95845 (review), 2nd subblock.

(cherry picked from commit bdb2cf8e913c041f26e8976abe58414819b3e8ff)